Stable fuel oil compositions



United States Patent OfiFice Patented Aug. l5, 1961 2,996,366 STABLEFUEL OIL COMPOSITIONS Arthur V. Churchill, Oakmont, and Edward Mitchell,

Rosedale, Pa., assignors to Gulf Research & Development Company,Pittsburgh, Pa., a corporation of Delaware No Drawing. Filed Aug. 12,1954, Ser. No. 449,515 17 Claims. (Cl. 44-66) This invention relates tostable fuel oil compositions, and more particularly to stable fuel oilcompositions comprising mixtures of straight run and catalyticallycracked fuel oil distillates.

Distillate fuel oil compositions containing mixed straight run andcatalytically cracked fuel oil distillates have proved exceptionallytroublesome with regard to sludge deposition during storage at normalatmospheric temperatures. It has been found that the sludgingcharacteristics of such mixed, or blended, fuel oil distillates arestrikingly poor, much poorer than can be accounted for from the knownsludging characteristics of the individual component fuel oildistillates alone. Although the exact cause for the unusual instabilityof mixed distillate fuel oils is not fully understood, the unusualcharacter and the unexpectedly large volume of sludge formed by suchmixed distillate fuel oils have led those skilled in the art to regardthe problem of sludge deposition in mixed distillate fuel oils asseparate and distinct from that of sludging in other oils.

More particularly, straight run distillate fuel oils containpredominantly parafiinic components. Sludge deposition in these oils,where such occurs, is considered to result from the presence of minoramounts of components that are not normally present and which impartinstability to the otherwise stable oils, e.g., impurities picked upduring refining, rather than from the inherent instability of the oilitself. The problem of sludge formation in such oils is consideredessentially one involving oxidation and the formaton of insolubleoxygenated products.

catalytically cracked fuel oil distillates on the other hand are rich inolefinic, aromatic and mixed olefinicaromatic compounds. Sludging insuch oils is considered to involve primarily condensation and/orpolymerization type reactions which result in the formation of insolublereaction products of relatively high molecular weight.

Still further, sludge deposition in blends of straight run andcatalytically cracked fuel oil distillates is an entirely distinctproblem from that for either component oil. While the sludge formed insuch blended fuel oils very probably contains some sludge of the typeformed in each component oil, the sludge formed in blended fuel oils isconsistently greatly in excess of the amount that can be accounted forfrom the known sludging tendencies of the individual component oils,thus indicating the existence of a special problem.

The problem of sludge deposition in mixed straight run and catalyticallycracked fuel oil distillates is not only separate and distinct from thatof sludge deposi-: tion in individual distillate fuel oils, but alsofrom that of sludge deposition in lubricating oils and from that of gumformation in gasolines. In the former instance sludge formation isattributed to the high temperature oxidation of the highly parafiiniccomponents contained in the loil, the reaction of acidic oxygenatedproducts with metals contacted therewith, and, in the caseof crankcaselubricants, sludge formation is additionally attributed to the presenceof foreign materials such as water, dust particles, carbon, incompletelyburned fuel and the like.

Gum formation in gasolines on the other hand is attributed primarily tothe oxidation of olefinic linkages (as opposed to oxidation ofparafiinic compounds). Moreover, the gums formed in gasoline are notnormally insoluble in the fuel as is the case with sludge; instead,deposition of gums from gasoline occurs upon vaporization of the latter,rather than during storage as is the case with blended fuel oils.

The present invention relates to fuel oil compositions comprising mixedcatalytically cracked and straight run fuel oil distillates, whichcompositions possess improved sludging characteristics. It has beenfound that. such improved distillate fuel oil compositions can beobtained by incorporating in the mixed oil a small, sludge inhibitingamount of a salt of a carboxylic acid containing at least 8 carbon atomsper molecule and a 1,3-diaminopropane having the general formula:

where R is an aliphatic radical containing from 8 to 30 carbon atoms.For example, excellent results are obtainable with fuel oil compositionshaving incorporated therein small amounts of the carboxylic acid saltsof 1,3-diaminopropanes of the type indicated above, where R is an alkylor alkenyl group containing 12 to 18 carbon atoms.

The addition of very small amounts of salts of the foregoing type toblended distillate fuel oils containing both straight run andcatalytically cracked components has been found to produce a markedimprovement in the sludging tendencies of the oils. Naturally, thevarious individual salts of the herein disclosed class do not possessexactly identical effectiveness, and the most advantageous concentrationfor each such salt will depend to some extent upon the particularcompound used. Also, the minimum effective inhibitor concentration mayvary somewhat according to the nature of the mixed fuel oil utilized. Ingeneral, however, the herein disclosed salts are useful inconcentrations of as little as about 0.005 percent, up to about 1.0percent by weight of the composition. Major improvement of the sludgingcharacteristics of mixed fuel oils is usually obtainable byincorporation therein of from about 0.01 to about 0.05 percent byweight, of a salt of the herein disclosed class. However, in some casesit can be advantageous to add as much as 0.1 percent by weight of theinhibitor, and in unusual instances it may even be desirable to add asmuch as 1. 0 percent by weight of the inhibitor.

The inhibitor compounds included by this invention may be incorporatedin the mixed fuel oil in any suitable manner. Thus, the salts may beformed in situ in the oil, or they may be added, per se, to the mixedfuel oil, either directly or in the form of concentrated solutions ordispersions, either immediately after the mixture of distillate fueloils is formed or after the mixture has been stored for a substantialperiod of time. In the latter case, the additives of this invention tendto transform previously formed sludge into an unobjectionable form.Alternatively, the sludge inhibiting salts of this invention may beformed in situ in, or added per se or in the form of concentratedsolutions or dispersions to, either the straight run or thecatalytically cracked fuel oil distillates prior to blending of thesecomponents to form a mixed fueloil. In either case, addition of thepreformed additives is preferred. Suitable concentrates containing theinhibitor compounds of this invention comprise, for example, mineral oilsolutions or dispersions containing from about 20 to weight percent, andpreferably from about 40 to 60 weight percent active ingredient. Ininstances where the concentrates are in the form of dispersions it maybe desirable to heat the concentrates and/or the fuel oil distillates tobe inhibited, e.g. to a temperature of from to F.,

the diamine in a 2:1 mol ratio.

in order to expedite blending. An alternative practice involves the useof concentrated solutions of the disclosed inhibitors in solvents, otherthan mineral oils,

which have a high degree of solubility for the inhibitors of thisinvention and which do not adversely affect the sludging tendencies ofthe distillate fuel oils. Examples of such concentrates are the 50weight percent solutions of the monoand dioleates of3-tallow-aminopropylamine in benzene, isopropanol and methyl isobutylketone.

The class of distillate fuel oils to which this invention is applicableincludes mixtures of straight run and catalytically cracked distillatefuel oils such as areused for domestic heating and for heating purposesin some industrial processes, typical of which are the so-ealled No. 2fuel oils, i.e., distillate oils boiling within the approximate range of350 to 750 F. andhaving a minimum API gravity of about 26. i i

The problem of stabilizing such oils, with which problem the presentinvention is concerned, is unique, and it exists only when acatalytically cracked fuel oil distillate and a straight run fuel oildistillate are combined in such proportions as to cause a substantialeffect of the kind previously described. The invention is important whenthe ratio of thevolume of the catalytically cracked to the straight runoil iswithin the range of about 9:1 and about 1:9. It is especiallyadvantageous when applied to mixed oils containing these oils in avolume ratio within the range of 4:1 and 1:4.

As indicated, the salts that are useful for the purposes of thisinvention are carboxylic acid salts of 1,3-diaminopropanes that containa secondary amine grouping. Such salts are prepared by neutralizationwith a carboxylic acid of one or both of the amino groups of a1,3-diaminopropane that contains a secondary amino grouping. Theneutralization reaction normally takes place spontaneously at roomtemperature with evolution of heat, but in some cases moderate heatingmay be desirable in order to accelerate the reaction. In no case shouldthe reaction be carried out at temperatures in excess of about 195 F.,since decomposition of the ammonium salt may occur with prolongedexposure to temperatures substantially in excess of this limit. The molratio of the reactants, i.e., the carboxylic acid and the diamine,varies according to the degree of neutralization desired and accordingto the number of carboxyl groups in the acid,

lesser amounts of polycarboxylic acids being required for the desireddegree of neutralization than of monocarboxylic acids. By way ofillustration, partial neutralization of the 1,3-diaminopropanes may beobtained by reacting a monobasic carboxylic acid with the diamine in a1:1 mol ratio, and complete neutralization may be obtained by reacting amonobasic carboxylic acid with partial neutralization of the diamine maybe obtained by reacting a dibasic acid therewith in a 1:2 mol ratio andcomplete neutralization of the diamine may be ob tained by reacting adibasic acid therewith in a 1:1 mol ratio.

The diaminopropanes that form salts included by this invention may beillustrated by the generic formula:

where R is an aliphatic radical containing from 8 to 30 carbon atoms.Thus, the present invention includes, for example, the use of salts oflong chain alkyl-, alkenyland alkadienylaminopropylamines. Specificexamples of such compounds are salts of the hereinafter disclosedcarboxylic acids and 3-octylaminopropylamine,3-tetradecylaminopropylamine, 3 tetradecenylaminopropylamine, 3eicosylaminopropylamine, 3 eicosenylaminopropylamine, and V 3triacontanylaminopropylamine. Within the general class of the carboxylicacid salts of l,3-diaminopropanes included by this invention, the saltsOn the other hand, the

and cyclohexyl stearic acids.

secondary amine grouping contains at least 12, and preferably from 12 to18, carbon atoms are especially effective. Examples of salts consideredto be exceptionally effective are the carboxylic acid salts of the3-dodecyl-, the 3-hexadecylaminopropylamines, and especially the 18carbon alkyl-, alkenyl-, and alkadienylaminopropylamines, such as the3-octadecyl-, 3-octadecenyl-, and 3- octadecadienylaminopropylamines.Although salts of aliphatic hydrocarbon N-substituted1,3-diaminopropanes are preferred, the invention also includes salts ofdiamines in which the N-substituent of the secondary amine grouping isitself substituted with one or more groups that contain elements such asoxygen, sulfur, nitrogen or halogen, and that do not interfere with theoil-solubility of the salt. Representative examples of carboxylic acidsalts of 1,3-diaminopropanes containing substitutents of this kind aresalts of 3-ricinoleylaminopropylamlne and-3-(chlorostearyl)aminopropylamine.

Carboxyl-ic acids that form salts included by this invention areoil-soluble monoor polybasic carboxylic acids which contain at least 8carbon atoms per molecule and which are capable of reacting with adiamino compound of the kind described above to form a substitutedammonium salt. The invention particularly includes salts of long chain,saturated or unsaturated, oil-soluble fatty acids. Specific examples ofsuch acids include caprylic, myristic, tetradecenoic, arachidic,eicosenoic and triacontanoic acids. Mixtures of long chain fatty acidssuch as those obtained from the saponification of natural fats and oilsare also suitable. Examples of such acids are coconut, soya, tallow andtall oil fatty acids. Theinvention is not limited to the use of salts ofopen'chain carboxylic acids but also includes salts of alicyclicoilsoluble carboxylic acids, such as, for example, alkyl cyclopentanoicacids, alkyl cyclohexanoic acids, and the naphthenic acids, e.g., themixed, alicyclic monocarboxylic acids recovered by alkali washing ofpetroleum distillates such as kerosene, naphtha, gas oil, andlubricating distillates. The thus'derived acids are considered tocomprise mixtures containing from about 7 to 30 carbo'n atoms permolecule, which mixtures have average molecular weights ranging fromabout 200 to about 450. The invention not only includes the salts ofpetroleum naphthenic acids but also the salts of synthetic naphthenicacids, such as cyclohexyl acetic, cyclohexyl propionic,

The invention further includes the use of salts of oil-soluble polybasiccarboxylic acids. Representative examples of such salts are salts ofazelaic, sebacic, dodecanedioic and hexadecanedioic acids, as well asdimerized unsaturated fatty acids such as dilinoleic acid. Othersuitable oil-soluble disbasic carboxylic acids are the long chain alkylor alkenyl, or cycloalkyl substituted succinic acids or similarlysubstituted glutaric or thiaglutaric acids, representative examples ofwhich are dodecenylsuccinic acid and 2,4-dinaphthenyl,3- thiaglutaricacid. The latter may be prepared as indicated in the copendingapplication of Pellegrini et al, Serial No. 387,308, filed October 20,1953, now abandoned. The invention includes acids "which are substitutedwith groups containing sulfur, oxygen, halogen, etc., which do notadversely afiect the oil-solubility thereof, such as ricinole ic acid orchlorostea'ric acid. 7

It is not necessary that either the oil-soluble carboxylic acid or theN-substituted 1,3-diaminopropane :be employed in pure form. If desired,mixed salts formed by reacting mixed carboxylic acids, such as thosederived from the saponification of natural oils or fats, the mixedN-substituted 1,3-diaminopropanes, such as those resulting when thealiphatic N-substituent of the secondary amine grouping is a monovalentaliphatic hydrocarbon radical derived from mixtures of fatty. acidsobtained from naturally occurring fats and oils. In such cases theN-substituents will be monovalent, straight chain hydrocarbon radicalscontaining from 8 to 20 carbon atoms.

Thus, for example, the mixed, coconut, soya or tallow fatty acid saltsof 3-tallow"-, 3-soyaor 3-cocoaminopropylamines are satisfactory for thepurposes of this invention, where the respective N-substituents aremixed alkyl and unsaturated alkyl groups derived from animal tallow (Cfatty acids, soybean (C fatty acids, and coconut (C fatty acids.

The effectiveness of the herein disclosed class of salts to improve thesludging characteristics of mixed straight run and catalytically crackeddistillate fuel oils is considered to be peculiar thereto in view of thefact that carboxylic acid salts of low molecular weight alkylenediamines, even though of similar structure, not only fail appreciably toinhibit sludge deposition in such mixed distillate fuel oils, but inmany instances actually function as sludge accelerators.

The utility of the herein disclosed class of carboxylic acid salts ofN-substitluted 1,3-diaminopropanes has been demonstrated by subjectingmixtures of catalytically cracked and straight run fuel oil distillatescontaining various representative salts of the class included by theinvention to a standard, accelerated stability test. The test sampleswere made up by adding the desired concentration of each additive to betested to separate samples of various fuel oil mixtures containing 50percent by volume Eastern Venezuela straight run No. 2 fuel oildistillate and 50 percent by volume catalytically cracked No. 2 fuel oildistillate and having varying sludging characteristics. The results ofthe testing of fuel oil compositions containing the following additivesare presented elsewhere herein as illustrative of the lbenefitsobtainable by this invention: the monooleate of3-tallow-aminopropylamine (prepared by reacting oleic acid and 3-tallow-aminopropylamine in a 1:1 mol ratio), the dioleate of3-"tallow-aminopropylamine (prepared by reacting oleic acid and3-tallow-aminopropylamine in a 2:1 mol ratio), the substantially neutraldiammonium 2,4-dinaphthenyl-3-thiaglutarate of 3t2LllOW-3Hhil101)l0-pylamine (prepared by reacting 2,4-dinaphthenyl-3- thiaglutaric acid and3-tallow-aminopropylamine in a 1:1 mol ratio), the di-(3-an1inopropyl,tallow-ammonium)2,4-dinaphthenyl-3-thiaglutarate (prepared by reacting2,4-dinaphtl1enyl-3-thiaglutaric acid with 3-tallow-aminopropylamine ina 1:2 mol ratio), the mononaphthenate of 3-"tallow-aniinopropylamine(prepared be reacting petroleum naphthenic acids with3-tallowaminopropylamine in a 1:1 mol ratio), the dinaphthenate of3-tallow-aminopropylarnine (prepared by reacting petroleum naphthenicacids with 3-tallow-aminopropylamine in a mol ratio of 2:1), themono-(Z-ethylhexoate) of 3-"tallow"-aminopropylamine (prepared byreacting 2- ethylhexoic acid with 3-tallow-aminopropylamine in a 1:1 molratio), and the di-(Z-ethylhexoate) of 3-tallowaminopropylamine(prepared by reacting Z-ethylhexoic acid with 3-"talloW-aminopropylaminein a 2:1 mol ratio). The naphthenic acids referred to above had anaverage molecular weight of 258 and a boiling range of 150 to 196 C. at0.7 to 0.9 of mercury.

In order to illustrate by comparison the unique nature of the benefitsobtainable from the use of the paitioular class of salts included bythis invention, there are also presented below the results obtained fromtesting similarly compounded and tested fuel oil compositions containingthe mono and dinaphthenic acid salts of ethylene diamine (prepared byreacting naphthenic acids and ethylene diamine in a 1:1 and a 2:1 molratio).

The 3-"tallow-aminopropylamine previously adverted to was a mixturecontaining about 80 percent active ingredients, calculated as diamines,wherein the N-substituent of the secondary amine grouping was a mixtureof alkyl and alkenyl radicals containing from 14 to 18 carbon atomsderived from the mixed fatty acids obtained from the saponification ofanimal tallow. The mixture contained predominantly3-octadeceny1aminopropylamine,

or 3-oleylaminopropylamine, together with lesser proportions of 3-octadecyland 3-hexadecylaminopropylamines and still smaller proportionsof 3-octadecadienyland 3- tetradecylaminopropylamines. The mixture had amelting range of 44 to 48 C., a theoretical molecular weight of 320 anda combining weight (calculated on percent active ingredients) of 400.

The stability test referred to above was carried out on theabove-indicated mixed fuel oil compositions by heating 600 gram samplesof the fuel oil compositions for a period of 16 hours at 210 F. inloosely stoppered, onequart, clear glass bottles. Following the heatingperiod each test sample was cooled to room temperature and filtered bysuction through a tared, medium porosity, fritted glass Gooch-typecrucible. The sludge in each crucible was washed with heptane. Completeremoval of the sludge adhering to the inside of the bottles was obtainedby means of a rubber policeman and heptane. The respective crucibleswere dried in an oven maintained at 210 F. for 1 hour, cooled in adesiccator and reweighed. The increase in weight was recorded asmilligrams of sludge per 600 grams of oil.

The results obtained in the testing of the above-described fuel oilcompositions are set forth below in tabular form. The fuel oil blendreferred to as Blend A in the table was found to have an API gravity of28.7, a specific gravity (60/60 F.) of 0.8833,. a viscosity of 35.6 SUSat R, an NPA color of 2-, a bromine number of 16.5, a pour point of 0 R,an olefin content of 22.3 weight percent (calculated), an aromaticcontent of 26.2 volume percent, a flash point of R, an aniline point of116 R, an acid number of 0.05, an ash content of less than 0.01 percent,calculated as oxides, an initial boiling point of 385 F. and an endpoint of 642 F. The foregoing values are typical of, although notnecessarily identical with, those obtained for Blend B and Blend C.

Table A Sludge, Fuel Oil Compositions mg./60O g. Oil, After 16 Hrs.

1. Blend A50/50 Mixture of E.V.S.R. and F.C.C. N0. 2

Fuel Oil Distillate 18. 2 2. Blend A plus 0.02 Wt. Percent Monooleate of3-T low-aminopropylamine 2. 0 3. Blend A plus 0.02 Wt. Percent Dioleateof 3-Tallowaminopropylamine 2. 3 4. Blend A plus 0.05 Wt. Percent2,4-Dinaphthenyl-3- Thiaglutarate of 3-.Ta1low"-ami110propylamine 5. 15. Blend A plus 0.05 Wt. Percent di-(3-Aminopr0pyl- Tallow-am1nonium)-2,4-Dinaphthenyl-3-Thiaglutarate 3.1 6. Blend A plus 0.05 Wt. PercentMouonaphthenate oi 3- Tallow-an1inupropylamine 1. 3 7. Blend A'plus 0.02Wt. Percent Mononaphthenate 01' 3- "Tallow-aminopropylamine 4. 2 8.Blend A plus 0.01 Wt. Percent Mononaphthe TalloW-an1i nopr0pylamine 4. 69. Blend A plus 0.05 Wt. Percent Mono-2-Ethy1hex0ate of3-Tallow"-arninopropylamine 3. 9 l0. Blend A plus 0.05 Wt. PercentDi-2-Ethylhexoate of 3- "Tallow"-aminopropylamine 4. 9 11. Blend B50/50Mixture of E.V.S. and FCC. N0. 2

Fuel Oil Distillate 9. 8 12. Blend B plus 0.05 Wt. Percent Dinaphthenateof 3- "Tallovv-amin0propylamine 3. 9 13. Blend C50/50 Mixture ofE.V.S.R. and F.C.C. No. 2

Fuel Oil Distillate 31. 8 14. Blend 0 plus 0.02 Wt. PercentEthylenediamine Mononaphthenate 315. 0 15. Blend 0 plus 0.02 Wt. PercentEthylenediamine Dina phthenate 34. 8

Compositions 2, 3, 4, 5, 6, 7, 8, 9, 10 and 12 in the foregoing tableare specific embodiments of the invention. The results shown in thetable for these compositions are considered typical of those obtainablewith the carboxylic acid salts of the class included by the invention.Comparison of the results obtained for Compositions 2 to 10, inclusive,and for Composition 12 with the results obtained for corresponding blankCompositions 1 and 11 clearly indicates the marked improvement in thesludging characteristics of mixed distillate fuel oils I that isobtainable with the salts included by this invention. On the other hand,comparison of the sludging characteristics of Compositions 14 and withthose of corresponding blank Composition 13 indicates that salts otherthan those included by the invention, even though of related structure,do not improve the sludging characteristics of mixed catalyticallycracked and straight run fuel oils. Indeed, many such compounds, asshown by the results set forth in the table for Composition 14, have amarked detrimental effect upon the sludging tendencies of saidmixed'fuel oils.

The sludge inhibiting additives of this invention are especiallyadvantageous in that they are. essentially ashless in character.

It will be understood that the foregoing specific embodiments of theinvention are merely illustrative and that other members of the class ofsludge inhibiting salts included by the invention can be used in thesame concentrations or in other equivalent concentrations within theranges disclosed, to prepare mixed catalytically cracked and straightrun fuel oil compositions having similarly improved sludgingcharacteristics. Examples of other specific embodiments of the inventionare mixtures of straight run and catalytically cracked fuel oildistillates within the ratios of 9:1 and 1:9 by volume, e.g., 411,2:1,1:1, 1:2 and 1:4 by volume, having incorporated therein from' 0.005 to1.0 percent by weight, e.g., 0.01, 0.02, 0.03, 0.04, 0.05, 0.1 percentby weight, of the monoand dilaurates, monoand dimyristates, monoanddipalmitates, monoand distearates, monoand dilinoleates and monoanddinaphthenates of 3-dodecylaminopropylamines, 3-tetradecylaminopropylamine, 3- hexadecylarninopropylamine, 3octadecylaminopropylamine and 3-octadecenylaminopropylamine. Examples ofother suitable compounds which can be substituted in the foregoingembodiments are salts 'of sebacic acid, azelaic acid, dodecyl,dodecenyl, and octadecyl succinic acids and the foregoing N-substitutedaminopropylamines.

If desired, the stable fuel oil compositions of this invention maycontain, in addition to the additives disclosed herein, otherimprovement agents such as for example, oxidation inhibitors, flashpoint control agents, corrosion inhibitors, anti-foam agents, ignitionquality improvers, combustion improvers and other additives adapted toimprove the oils in one or more respects.

It will be apparent to those skilled in the art that many modificationsand variations of the invention may be resorted to without departingfrom the spirit thereof. Accordingly, only such limitations should beimposed as are indicated in the claims appended hereto.

We claim:

1. A fuel oil composition comprising a major proportion of a mixture ofstraight run and catalytically cracked distillate fuel oils tending'todeposit sludge and containing a small amount of an oil-soluble salt of acarboxylic acid that contains 1 to 2 carboxyl groups and at least 8carbon atoms per molecule, and a compound of the type indicated by thegeneral formula:

cent by weight of said mixture of oils.

4. The fuel oil composition of claim 1 wherein R is a radical selectedfrom the group consisting of alkyl and alkenyl groups containing 12 to18 carbon atoms. 7

5. A fuel oil composition comprising a major proportion of a mixture ofstraight run and oatalytically cracked distillate fuel oils tending todeposit sludge and containing a small amount of a monooleate of3.-octadecenylaminopropylamine, said small amount being sufficient toinhibit sludge deposition from said mixture of oils.

6. A fuel oil composition comprising a major proportion of a mixture ofstraight run and catalytically cracked distillate fuel oils tending todeposit sludge and containing a small amount of a monooleate of mixed3-alkyland 3-alkenylaminopropylamines wherein said alkyl and alkenylsubstituents contain 14 to 18 carbon atoms, and the predominantsubstituent is octadecenyl, said small amount being sufficient toinhibit sludge deposition from said mixture of oils.

7. A fuel oil composition comprising a major proportion of a mixture ofstraight run and catalyticaly cracked distillate fuel'oils tending todeposit sludge and containing a small amount of a dioleate of3-octadecenylaminopropylamine, said small amount being sufficient toinhibit sludge deposition from said mixture of oils.

8. A fuel oil composition comprising a major proportion of a mixture ofstraight run and catalytically cracked distillate fuel oils tending todeposit sludge and containing a small amount of a dioleate of mixed3-alkyland 3-alkenylaminopropylamines wherein said alkyl and alkenylsubstituents contain 14 to 18 carbon atoms, and the predominantsubstituent is octadecenyl, said small amount being sufficient toinhibit sludge deposition from said mixture of oils.

9. A fuel oil composition comprising a major proportion of a mixture ofstraight run and catalytically cracked distillate fuel oils tending todeposit sludge and containing'a small amount of a mono-2-ethylhexoate of3octyldecenylaminopropylamine, said small amount being suflicient toinhibit sludge deposition from said mixture of oils.

10. A fuel oil composition comprising a major proportion of a mixture ofstraight run and catalytically cracked tion of a mixture of straight runand catalytically cracked distillate fuel oils tending to deposit sludgeand containing a small amount of a di-Z-ethylhexoate of 3-oc tadecenylaminopropylamine, said small amount being sufficient to inhibitsludge deposition from said mixture of oils. I

12. A fuel oil composition comprising a major proportion of a mixture ofstraight run and catalytically cracked distillate fuel oils tending todeposit sludge and containing a small amount of a di-Z-ethylhexoate 'ofmixed 3- alkyland 3-alkenylaminopropylamines wherein said alkyl andalkenyl substituents contain 14 to 18 carbon atoms, and the predominantsubstituent is octadecenyl, said small amount being sufficient toinhibit sludge deposition from said mixture of oils.

13. A fuel oil composition comprising a major proportion of a mixture ofstraight run and catalytically cracked distillate fuel oils tending todeposit sludge and containing a small amount of a mononaphthenate of3-octadecenylaminopropylamine, said small amount being sulficient toinhibit sludge deposition from said mixture of oils.

14. 'A fuel oil composition comprising a major proportion of a mixtureof straight run and catalytically cracked distillate fuel oils tendingto deposit sludge and containing a small amount of a mononaphthenate ofmixed 3-alkyland 3-alkenyla1r1inopropylamines wherein said alkyl andalkenyl substituents contain 14 to 18 carbon atoms,

a and the predominant substituent is octadecenyl, said small amountbeing sufiicient to inhibit sludge deposition from said mixture of oils.

15. A fuel oil composition comprising a major proportion of a mixture ofstraight run and catalytically cracked distillate fuel oils tending todeposit sludge and containing a small amount of a dinaphthenate of3-octadecenylaminopropylamine, said amount being suflicient to inhibitsludge deposition from said mixture of oils.

16. A fuel oil composition comprising a major proportion of a mixture ofstraight run and catalytically cracked distillate fuel oils tending todeposit sludge and containing a small amount of a dinaphthenate of mixed3-alkyland 3-alkenylaminopropylamines wherein said alkyl and alkenylsubstituents contain 14 to 18 carbon atoms, and the predominantsubstitutent is ootadecenyl, said small amount being sufficient toinhibit sludge deposition from said mixture of oils.

17. A fuel oil composition comprising a major proportion of a mixture ofstraight-run and catalytical-ly cracked distillate fuel oils tending todeposit sludge and contain- References Cited in the file of this patentUNITED STATES PATENTS 2,329,251 Chenicek Sept. 14, 1943 2,684,292 Caronet a1. July 20, 1954 2,688,595 Fainman Sept. 7, 1954 2,700,612 OhenicekJ an. 25, 1955 2,736,641 Mattson et a1 Feb. 28, 1956 2,736,658 Pfohl eta1 Feb. 28, 1956 2,771,348 Meguerian Nov. 20, 1956

1. A FUEL OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF A MIXTURE OFSTRAIGHT RUN AND CATALYTICALLY CRACKED DISTILLATE FUEL OILS TENDING TODEPOSIT SLUDGE AND CONTAINING A SMALL AMOUNT OF AN OIL-SOLUBLE SALT OF ACARBOXYLIC ACID THAT CONTAINS 1 TO 2 CARBOXYL GROUPS AND AT LEAST 8CARBON ATOMS PER MOLECULE, AND A COMPOUND OF THE TYPE INDICATED BY THEGENERAL FORMULA: